The objects of study are the areas identified as SMSA's in 1960 and 1970. The relative importance of each demographic component of population change (reproductive change and net migration) is examined and related to selected ecological, demographic, social, and economic characteristics of the SMSA and/or its population. This analysis is performed as well for central city and noncentral city portions of the SMSA's and, for a subset of areas, is also performed by color. The basic analytical approach is correlation and regression.